from openpyxl import load_workbook

wb = load_workbook('test14.xlsx')
ws = wb.active

# print(list(ws.columns))
# exit()
i = 1
for col in ws.columns:
    # print(col)
    for c in col:
        # print(c)
        # print(c.value)
        c.value = c.value + str(i)
    i += 1
wb.save('test14.xlsx')